Rotary valve for metallurgical vessels and the like

ABSTRACT

A rotary-valve mechanism is provided for controlling the discharge of molten material from a container (primarily molten metal such as steel from casting ladles etc.) which mechanism is fitted at the base of the container and comprises a stationary refractory upper plate and a rotatable refractory lower plate below it, with the upper surface of the lower plate in contact with the under surface of the upper plate, the two plates being pierced with flow passages which can be brought into and out of register by rotation of the lower plate. The contact surfaces of the two plates are flat and lie in a plane normal to the axis of rotation, the lower plate is provided with an axial discharge orifice to which the flow passages lead, and the flow passages are so formed that the flow through them, in the fully open and in at least one partially position, is substantially symmetrical with regard to the axis of rotation; this latter requirement is met by the provision of diametrically opposed flow passages in the upper plate lead by way of opposed recesses in the upper surface of the lower plate to the discharge orifice. The two plates are replaceable from below the ladle.

United States Patent Fehling [54] ROTARY VALVE FOR METALLURGICAL VESSELS AND THE LIKE [72] Inventor: Hans Reinhard .Fehling, Zurich,

Switzerland 73 Assignee: Didier-Werke A.G., Wiesbaden,

Germany 22 Filed: Feb. 20, 1970- 21 Appl. Natl 3,110

[30] Foreign Application Priority Data Feb. 22, 1969 Great Britain ..9,662/69 52 use]. .222/531, 222/555, 239/540, 251/208 51 int. Cl. ..B22d37/00 [58] Field of Search ..222/566, 531, 537, 548, 555; 164/136, 281, 335, 337; 137/625.3l; 251/208; 239/538, 540

[56] References Cited [151 3,685,706 51 Aug. 22, 1972 873,497 12/ 1907 V Buell ..222/548 ABSTRACT A rotary-valve mechanism is provided for controlling the discharge of molten material, from a container- (primarily molten metal such as steel from casting ladles etc.) which mechanism is fitted at the base of the container and comprises a stationary refractory upper plate and a rotatable refractory lower plate below it, with the upper surface of the lower plate in contact with the under surface of the upper plate, the two plates being pierced with flow passages which can be brought into and out of register by rotation of the lower plate. The contact surfaces of the two plates are flat and lie in a plane normal to the axis of rotation, the lower plate is provided with an axial discharge orifice to which the flow passageslead, and the flow passages are so formed that the flow through them, in the fully open and in at least one partially position, is substantially symmetrical with regard to the axis of rotation; this latter requirement is met by the providie.

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SHEET 5 BF 5 INVENTOR HANS REINHARD FEHLING his ATTORNEYS CROSS-REFERENCE TO RELATED APPLICATIONS Reference is made to British Pat. Application No. 09662/69 of Feb. 22, 1969, Didier-Werke A.G. from which priority is claimed.

The invention relates to a flow regulating and closure device for metallurgical vessels and like vessels containing molten material (melt) at high temperature, particularly ladles and the like in the steel industry.

It is known to use a sliding gate valve device in which regulation and closure is effected by sliding two perforated plates, one fixed and the other moving, over I each other. Both a linear and a rotary sliding movement have been proposed in the past.

Such rotary valves have many attractions but none of the proposals made in the past have had any practical success. Particularly at veryhigh temperature, as in the case of modern steel casting ladles containg up to 350 tons of metal, the operating conditions are very severe:

1. Even the best of present refractory materials have a limited life when subjected to the erosive attack of a high speed steel stream.

2. Erosion interferes with the proper functioning of the valve and may even destroy the latter.

3. In view of this attack it has been found particularly difficult to throttle the valve over prolonged periods.

4. Due to the speed of the steel stream and its high fluidity it is difficult to obtain a smooth streamlined discharge of the metal over a wide range. Usually the jet becomes unstable when the valve is throttled beyond a certain degree.

5. Under working conditions there are substantial temperature gradients in the refractory parts in contact with the melt. This causes significant differences in thermal expansion which in turn make it difficult to obtain a tight fit between the parts which are in relative sliding engagement.

6. Due to the inevitable wear and tear on the refractory parts maintenance and replacement has to take place at frequent intervals. In many cases it is even the rule to replace the principal refractory parts of the valve itself after each heat. It is necessary, or at least highly desirable, to carry out this work while the ladle is still hot. This imposes a number of design considerations, with regard to the weight of the parts and speed of breakdown and correct reassembly, which are difficult to meet.

It is the object of the present invention to overcome or reduce these difiiculties.

The present invention therefore provides a valve closure assembly for controlling the discharge of molten material from a container, comprising a stationary upper member and a rotatable member having an upper surface in contact with an under surface of the upper member, which members are pierced with flow passages which can be brought into and out of register by rotation of the lower member, characterized in that (a) said surfaces are flat and lie in a plane which is normal to the axis of rotation, (b) the lower member is provided with an axial discharge orifice, and (c) the flow passages are so constructed that the flow through them, in the fully open position and in a partially opened, or throttled, position or positions is substantially symmetrical with regard to the axis of rotation. Preferably the upper member has symmetrically disposed flow passages, and the lower member has symmetrically disposed recesses leading to an axial duct and to the discharge orifice.

In order that the invention may be better understood, reference will now be made to the accompanying drawings in which:

FIGS. 1 and 2 are vertical sections through two embodiments of rotary valve according to the invention;

FIG. 3'is a plan view,'on a larger scale, of the two members with one arrangement of their flow passages;

FIGS. 4A and 4B show these members in partly open or throttled positions, while FIGS. 4C and 4D show them in the fully opened and closed positions respectively;

FIG. 5 is a plan view showing another arrangement of the flow passages, .and

FIG. 6' shows one form of the flow. passage in the lower member and of the discharge orifice.

The vessel (e.g. a casting ladle) has a steel outer shell 1 with a refractory lining 2. At its bottom it has a refractory ring 3 into which a refractory ring 4, preferably of a more resistant refractory material and preferably replaceable from the exterior (from below), is mounted and secured against rotation.

Below ring 4 there is a stationary refractory upper plate member 5 and below this there is a rotatable refractory member 6. The under surface of member 5, and the upper surface of member 6. is flat. These two surfaces, which have to be finished e.g., by grinding to a high degree of flatness and smoothness, are in contact and lie in a plane which is normal to the axis of rotation of member 6. Members 5 and 6 form the operating parts of the valve.

The fixed plate 5 is tightly fitted to the ring 4 and is I so mounted that it is secured against rotation. It has symmetrically disposed windows 7 through which the melt canbe discharged.

The rotary plate 6 has symmetrically arranged cutouts 8 or recesses converging into an axial duct 9 through which the melt is discharged. It is preferable to provide an initially separate, but attached, nozzle 10, the length of which can be varied according tooperating requirements. The rotary plate 6 and the nozzle 10 are firmly mounted in a rotary support dish or base 11 made, for example, of cast iron.

In FIG. 1 the dish 11 is held in position by bevelled wheels 12 (which are preferably three in number, symmetrically disposed, and of which only one is shown) mounted for rotation round vertical studs 12a fixed to the steel frame of the ladle.

In FIG. 2, parts which correspond with equivalent parts in FIG. 1 have the same reference numbers. In this Figure, the dish 11 is held in position by three brackets 12 on which the underside of the dish slides as the dish is rotated.

The rotation of the dish may be effected by any suitable method. For small vessels where the friction force between the numbers 5 and 6 is small enough, this can be done by means of a lever. Another simple method is to effect the rotation by means of a steel cable 14 (FIG. 1) or by a ratchet and gear wheel. As will be appreciated from the description below, the rotary movement of the dish will never be much more than a quarter turn from the fully open to the fully closed positron.

In order to obtain a tight fit between the members and 6 it has been found necessary to. machine, grind, or lap the contact surfaces so that they are smooth and plane within less than 0.1 mm, and preferably less than 0.05 mm. For this purpose it is essential that neither of the two contacting surfaces is recessed within the two members.

The two members 5 and 6 are so designed and mounted that they can easily be replaced from outside while the ladle is hot.

The axis of the discharge duct 9 coincides with the axis of rotation so that there is no lateral movement of the steel jet during the opening, throttling or closing movements of the member 6.

In FIG. 1 the upper surface of the rotary member 6 is above the steel shell 1, i.e., as near to the bottom of the interior of the vessel as possible. This is desirable in cases (like small ladles) where there is danger of freezing of the metal above the level of this surface when the valve is closed. In FIG. 2 the upper surface of member 6 is below the steel shell. In this case it may be found desirable to prevent freezing by mounting the rotary member 6 on an insulating block 15.

FIG. 2 also shows an elongated nozzle for reaching below the steel surface of another vessel like the tundish above a continuous casting plant.

FIG. 3 is a plan view showing the fixed member 5 with the flow passages 7 and also showing (dotted lines) the cut-outs 8 and the central duct 9 of the rotary member 6.

It will be seen that the flow passages 7 are identical with one another and are symmetrically disposed at diametrically opposite locations with regard to the axis of rotation of member 6. The cut-outs 8 in the upper surface of member 6, which lead downwards into the axial duct 9, are identical in size and shape to one another and are also diametrically opposed FIGS. 4A and 4B show diagrammatically two different partly closed or throttled positions, FIG. 4C the fully open position and FIG. 4D the closed position, of one of the cut-outs 8 in relation to one of the flow passages 7.

An alternative arrangement of flow passages, cutouts, and duct is shown in FIG. 5. It will be seen that at each of two diametrically opposed locations the member 5 is provided with a plurality of circumferentially spaced flow passages 7a, 7b, and 7c of progressively increasing sizes, the outer margins of which passages are disposed on a circle which coincides with the outer margins of the cut-outs 8. Thus the member 6 may be turned from the fully closed position shown to three different positions in which the cut-outs 8 register with passages 7a, with passages 7b, and with passages 7c, to give, respectively, two different throttled flow positions and a fully opened position.

FIG. 6 shows alternative shapes for the cut-outs 8 and the duct 9.

It will be appreciated that in all the foregiving constructions and for all flow positions of the valve, the flow of the melt:

a. retains axial symmetry,

b. converges towards the central duct,

c. has no, or substantially no, flow component inducing a rotary (vortex) movement of the melt in the discharge duct and the jet itself.

For this reason it is possible to regulate the flow of steel over a very wide range without the drawbacks and difiiculties mentioned above.

In the constructions shown in FIGS. 1 and 2 the refractory parts 5, 6 and 10 require the most frequent replacement as they are subject to the attack of steel flowing at high velocity. This is very easily carried out, as it is only necessary to loosen or undo three nuts. Particularly in FIG. 1 the weight of the parts is reduced to a minimum.

The correct mounting of a new set of refractory parts 5 and 6 requires great care.

It will be appreciated that the fixed member 5 has to be mounted first. In order to fulfil the twin requirements of tight fit and horizontal alignment of its bottom surface, it is necessary to provide a sufficiently thick layer of highly refractory mortar between it and the bottom surface of ring 4. It is preferable to recess the ring into the top of member 5.

Corresponding care has to be taken with the mounting of the rotary member 6 in the dish 11, so that the top surface of that member is parallel to the plane of rotation and the discharge duct isvconcentric with the axis of rotation. The necessary adjustment is provided by a suitable mortar bed between the refractory parts and the dish.

Even when the separate mounting of the members 5 and 6 is carried out with care, it may be difficult to ensure that the plane of rotation defined by the position of the wheels 12 (FIG. 1') or of the brackets 13 (FIG. 2) is truly parallel to the plane bottom surface of the fixed member 5. For this reason it may be desirable to arrange that the mounting of the wheels 12 or of the brackets 13 allows for small lateral and/or angular adjustments. For example, the bosses for the wheels may be fitted to a ball joint, or hinged, instead of being rigidly fixed to the steel shell of the ladle, as shown.

In the FIG. 1 construction the steel jet emerges in the immediate vicinity of the mounting holding the dish. It is therefore desirable to provide a protecting metal cap 16 which may be filled with insulating material 17.

As already mentioned the refractory parts 5, 6 and 10 should be highly resistant to the erosive action of the melt. For steel the best material so far available is a refractory containing over A1 0 Although in the constructions illustrated the flow passages in the upper plate 5, and the recesses in the lower plate 6, are placed at diametrically opposed locations, any other suitable symmetrical arrangement may be adopted. For example they may be placed at three locations which are equally spaced about the axis of rotation of plate 6.

What is claimed is:

1. In combination, a container for molten material having a stationary refractory ring and a valve closure assembly for controlling the discharge of molten material from the container, comprising a stationary refractory upper member and a rotatable refractory lower member having an upper surface in contact with an under surface of said upper member, said members are each pierced with at least two flow passages which can be brought into and out of register by rotation of said lower member, characterized in that (a) said surfaces are flat and lie in a plane which is normal to the axis of rotation of said members, (b) said lower member is provided with an axial discharge orifice, and (c) said flow passages are so constructed that the flow therethrough, in the fully opened and in a partially opened position is substantially symmetrical with regard to said axis of rotation.

2. A combination according to claim 1, wherein the upper member hasa plurality of symmetrically disposed flow passages and the lower member has a corresponding plurality of recesses, in its upper surface, leading to the axial discharge orifice for movement, by rotational movement of the lower member, into and out of register with the flow passages in the upper member.

3. A combination according to claim 2, wherein the flow passages are placed at diametrically opposed locations.

4. A combination according to claim 2, wherein the flow passages in the upper member are symmetrically disposed and shaped and their radial width increases in one direction of rotation of the lower member.

5. A combination according to claim 2, wherein the upper member has a plurality of circumferentially spaced flow passages which progressively increase in size in one direction of rotation of the lower member.

6. A'combination according to claim 1, having a rotary base on which the lower member is mounted, and bearing means for rotatably supporting said base from the underside of the container.

7. A combination according to claim 1, wherein the upper and lower members are replaceable from below the container.

T5333? UNITED STATES PATENT OFFICE CERTIFICATE OF c0 cw Patent No, 5 706 i Dated August 22, 1972 Ifiventofls) Hans Reinhard Fehling It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Page 1, after "Inventor. Fehling," the city "Zurich" should read -Zug-;

Page 1, under "References cited" the date "3/1963" given for the Hase et a1; patent should read 3/l96-8.

Signed and sealed this 8th day of May 1973. (571m Attest:

' EDEJAKD I'LFLE Attesting' Of TcHERmz. ROBi-EIPLT G TTSGHJLIK :Eicer v Commissioner of Patents 

1. In combination, a container for molten material having a stationary refractory ring and a valve closure assembly for controlling the discharge of molten material from the container, comprising a stationary refractory upper member and a rotatable refractory lower member having an upper surface in contact with an under surface of said upper member, said members are each pierced with at least two flow passages which can be brought into and out of register by rotation of said lower member, characterized in that (a) said surfaces are flat and lie in a plane which is normal to the axis of rotation of said members, (b) said lower member is provided with an axial discharge orifice, and (c) said flow passages are so constructed that the flow therethrough, in the fully opened and in a partially opened position is substantially symmetrical with regard to said axis of rotation.
 2. A combination according to claim 1, wherein the upper member has a plurality of symmetrically disposed flow passages and the lower member has a corresponding plurality of recesses, in its upper surface, leading to the axial discharge orifice for movement, by rotational movement of the lower member, into and out of register with the flow passages in the upper member.
 3. A combination according to claim 2, wherein the flow passages are placed at diametrically opposed locations.
 4. A combination according to claim 2, wherein the flow passages in the upper member are symmetrically disposed and shaped and their radial width increases in one direction of rotation of the lower member.
 5. A combinAtion according to claim 2, wherein the upper member has a plurality of circumferentially spaced flow passages which progressively increase in size in one direction of rotation of the lower member.
 6. A combination according to claim 1, having a rotary base on which the lower member is mounted, and bearing means for rotatably supporting said base from the underside of the container.
 7. A combination according to claim 1, wherein the upper and lower members are replaceable from below the container. 